Why is it hard, and costly to remove salt from water?

Question

Why is it hard, and costly to remove salt from water?

In: 4

Answer 1

Removing the salt from saltwater is relatively easy and people have known about it and been doing it for thousands of years.

The problem is that getting fresh water the natural way from rivers and lakes and from wells and rain is so cheap that normally we don’t bother.

We have gotten so used to cheap and easily accessed water that when we see the cost for desalination it seems enormous to us.

The normal way we treat and waste fresh water becomes unsustainable when you actually have work hard and pay for it.

If you are used to getting water basically for free even the small price it costs to turn slat water into fresh water will seem enormous.

A big problem is that in order to do desalination on a big scale you first need to build a lot of machinery and pipes and stuff and that takes time.

If you wait to build these plants until it really becomes necessary and it takes years to build them, that is a problem.

Other problems include the question of what to do with all the salt.

If you just throw it back into the ocean that will destroy the marine ecosystem near your plant and slating the earth is famously what you do to your enemies not your own land.

Then there is the problem that we get slat water from the ocean and people live on land. In order to get your freshly desalted water from the ocean to where people need it you need to pump that water up and inland.

Remember that we get much of our power from the energy of rivers flowing downhill.

To pump rivers worth of water uphill to where there are droughts you would need to basically at the equivalent of reverse hydropower plants that you need to power by something.

So to do desalination on a large scale you would need to start spending huge amounts of money on new power plants and desalination plants and pipes and power lines and other stuff many years before you could actually use them and the water that you would get from it would be so expensive that we couldn’t use it like we are used to.

It is not a good solution.